Encroaching threat

Zebra mussel invasion under way

September 4, 2011

DETROIT LAKES, Minn. While North Dakota is doing what it can to prevent the spread of aquatic nuisance species, the battle against them is well under way in Minnesota. Flowering rush is one of the invasive plants that has already taken hold in several Minnesota lakes. The dreaded zebra mussel is there too.

Rod Osvold, a Department of Natural Resources volunteer boat inspector, is among those on the front line against aquatic nuisance species.

Osvold has been working the boat ramps at Detroit Lake. He rises early every morning to beat fishermen and all users of watercraft to the lake so that he can both inspect and inform about aquatic nuisance species.

Article Photos

Kim Fundingsland/MDN - - Rod Osvold, a Minnesota Department of Natural Resources volunteer, inspects for aquatic nuisance species at a boat ramp on Big Detroit Lake. Of particular concern is the invasive zebra mussel that has become established in some Minnesota lakes.

"Pelican Lake, just south of us, it totally infected with zebra mussels," Osvold said. "We're trying to keep that out of this lake because it would ruin the economy. This is one of the best musky lakes in the state, so we don't want to lose that."

Zebra mussels, believed to have come to Minnesota via international ships entering the Great Lakes, multiply quickly and attach themselves by the thousands to virtually anything in the water. Osvold shows non-believers photographs of minnow buckets and boats left in the water where zebra mussels are present. Both are covered with zebra mussels.

'Could it happen?'

"It's very real," Osvold said. "I would think that North Dakota would probably adopt Minnesota law, along with Wisconsin and Iowa, so that we're all kind of working together. It's all education."

In the Land of 10,000 Lakes, an estimated 53 already are known to have zebras mussels. The ability for the mussels to enter new bodies of water in Minnesota is extremely high, particularly when considering all the boats and watercraft that use multiple lakes or rivers on any given day.

"People ask, 'Could it happen?'" said Lynn Schlueter, North Dakota Game and Fish Department special projects biologist. "It is in Minnesota and it has become well established. It's moving through that whole Pelican Lake chain and into the Red River of the North."

Velagers free floating zebra mussels in their earliest stages have already been found in tributaries leading into the Red River. That raises the potential that North Dakota boaters frequenting the Red River and other bodies of water could transport zebra mussels across the state. Velagers are microscopically small.

"We're talking 1/64 of an inch or smaller, something like that," Schlueter said. "If you run your hand over your boat and get this sandpaper feel, it could be velagers. You can't really see them."

An adult zebra mussel can produce up to a million young in one year, meaning they have the ability to take over an entire lake floor in a relatively short period of time. They are small. Most are less than two inches in length, but their shells are so sharp that they cut bare feet with ease. More problematic is that zebra mussels feed by filtering water through their systems and extracting tiny food sources necessary to sustain other life in a lake. The result is a declining fishery and ugly recreational lake. Intake systems, docks and beaches are affected too.

North Dakota responded to the aquatic nuisance species threat last fall by enacting a regulation requiring the draining of all live wells and removing all water from watercraft before leaving a boat ramp area. In Minnesota the fine for having a plug in your boat while it is on the trailer is $500.

"We probably have less trouble with fishermen that anybody," Osvold said. "We're more worried about jet skis. Most people don't know how to drain a jet ski. After they drain it, they need to start it and get all the water out. I don't think I've talked to one person who knew how to do that. Basically, they all want a nice, clean lake and they're doing whatever they can to help."

"It takes what, seven minutes to clean a boat?" Schlueter said. "Take the precautions. It's the same thing we've been hammering on for years. Drain the water from the boat, the baitwell and the buckets. Pour some bleach down the livewell, down the bilge and rinse it out. It protects the lakes you want to go to."